If you have more than one child, you’ll have worked out for yourself that there’s a whole new dynamic going on that needs its own set of rules. I know a headmaster of a boys’ school who was asked by a local farmer, many decades ago now, if he could lend him one of his students to help with some farm work. The headmaster said he was sure he could find more than one willing helper if needed. The farmer declined saying, ‘One boy’s a boy, two boys is half a boy, and three boys is no boy at all’.

No doubt he’d have said much the same about girls. The fact is the more children you put together, the harder it becomes to keep them all on track. Not just because of the numbers, but because of the interactions between them. So this section is about the most important Rules you need to get you through when you have two or more children. It goes without saying that these Rules apply as much to step-siblings as to any others.